Book with that? Staff at a London branch of McDonald's. Photograph: Graeme Robertson

A little portion of literacy is set to be served up alongside the cheeseburgers and fries at McDonald's after the fast food chain committed to giving away 15m books with its Happy Meals over the next two years.

Following a pilot last year, which saw nine million books by Michael Morpurgo given away to children, McDonald's has now committed to a new, long-term campaign backed by the National Literacy Trust. By the end of 2014, the 1,200-restaurant chain says it will have handed out at least 15m fiction and non-fiction books to families in the UK, starting today with a five-week promotion in which a non-fiction book from DK's "Amazing World" series will be given away with every children's meal. The books cover topics including stars and planets, big cats and oceans.

McDonald's said it would also launch new "Happy Readers" £1 book offers, redeemable at WHSmith, and will additionally "lend its family-friendly restaurant environment and its focus on family fun to encouraging parents and children to enjoy books together". As well as DK, it will work with other publishers throughout the next two years on its promotions.

Alistair Macrow, McDonald's vice president, said that feedback about its book giveaway pilot had been "overwhelmingly positive", and that nine out of 10 parents wanted to see more book promotions from the fast food chain following the Morpurgo launch last year. "I've been surprised by statistics [from the National Literacy Trust] that show that one in three children don't own a book, and that half don't enjoy reading," he said. "This is a real opportunity for us to help shift the balance and put the fun back into reading."

Conal Presho, head of development at the National Literacy Trust, said that McDonald's initiative would "make a massive difference" to the number of children owning books in the UK. The NLT's research shows there is a clear link between book ownership and children's future success in life.

"When children own their own books, it makes a huge difference to their reading," Presho said. "This is a real opportunity to spark conversations, and is really positive. McDonald's is a company with huge reach across the UK."

Presho said that the NLT's focus "was not on the food side, but on getting books into kids' hands … Our focus is on using any way we can to encourage children to read, and to read anything they can, whether that's menus in restaurants, non-fiction books or magazines – anything which spreads children's enjoyment of reading," he said.